Method of forming a phase changeable structure

Abstract

The present invention relates to a method of forming a phase changeable structure wherein an upper electrode is formed on a phase changeable layer. A material including fluorine can be provided to the phase changeable layer and the upper electrode. The phase changeable layer can be etched to form a phase changeable pattern. Oxygen plasma or water vapor plasma can then be provided to the upper electrode and the phase changeable pattern.

1. A method of forming a phase changeable structure, the method comprising:
 forming a phase changeable layer on a lower electrode; 
 forming a conductive layer on the phase changeable layer; 
 etching at least a portion of the conductive layer with a first material having a chlorine-containing compound to form an upper electrode; 
 exposing the upper electrode and the phase changeable layer to a second material having a fluorine-containing compound; and 
 etching the phase changeable layer with a third material that is substantially free of chlorine to form a phase changeable pattern, in which the third material is different from the second material. 
 
   
   
     2. The method according to  claim 1 , further comprising removing substantially all of the first material before the exposing step. 
   
   
     3. The method of  claim 1 , wherein the fluorine-containing compound is selected from the group consisting of tetraflouromethane, trifluoromethane, difluoromethane, monofluoromethane, and any combination thereof. 
   
   
     4. The method of  claim 1 , wherein the second material further includes a diluent in a plasma state. 
   
   
     5. The method of  claim 4 , wherein the diluent is selected from the group consisting of helium, neon, argon, krypton, xenon, radon, and any combination thereof. 
   
   
     6. The method of  claim 1 , wherein the phase changeable layer comprises a calcogenide selected from the group consisting of germanium, antimony, tellurium, and any combination thereof. 
   
   
     7. The method of  claim 1 , wherein the fluorine-containing compound is selected from the group consisting of tetraflouromethane, trifluoromethane, difluoromethane, monofluoromethane, and any combination thereof. 
   
   
     8. The method of  claim 1 , wherein the conductive layer comprises a metal selected from the group consisting of tungsten, titanium, titanium nitride, tantalum, tantalum nitride, molybdenum nitride, niobium nitride, titanium silicon nitride, aluminum, titanium aluminum nitride, titanium boron nitride, zirconium silicon nitride, tungsten silicon nitride, tungsten boron nitride, zirconium aluminum nitride, molybdenum silicon nitride, molybdenum aluminum nitride, tantalum silicon nitride, tantalum aluminum nitride, copper, aluminum copper, alloys thereof, and any combination thereof. 
   
   
     9. The method of  claim 1 , wherein the exposing step is performed for about 5 seconds to about 15 seconds. 
   
   
     10. The method of  claim 4 , wherein the exposing step is performed in a chamber having a source electrode and a bias electrode, wherein power is applied at a ratio from about 2.5:1 to about 10:1 to the source electrode and the bias electrode, respectively, the chamber is maintained at a pressure from about 1 mTorr to about 10 mTorr, and a flow ratio from about 1:4 to about 3:2 of the fluorine-containing compound with respect to the diluent. 
   
   
     11. The method of  claim 1 , in which etching the phase changeable layer with the third material and exposing the upper electrode and the phase changeable layer to the second material are separate processes that are not performed concurrently. 
   
   
     12. The method of  claim 1 , in which the third material is different from the second material in that the third material is physically separate and distinct from the second material.